The glossary in the OGSA Data Architecture document currently defines "data set" as:
 

"An encoding of data in a syntax suitable for externalisation outside of a data service, for example communication to/from a data service.

Examples include a WebRowSet encoding of an SQL query result set, a JPEG encoded byte array, and a ZIP encoded byte array of a set of files."
 
Is this correct?  I'm not convinced that we use the term consistently to mean this - sometimes we just seem to mean a defined set of data items on a resource.  We may need to check each occurrence of the term (there aren't too many).
 
Best wishes,
 
Dave Berry
Deputy Director, Research & E-infrastructure Development
National e-Science Centre, 15 South College Street
Edinburgh, EH8 9AA                  +44 131 651 4039